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PET Resin
Preform molding
Preform design
Preform Animation
Blow Molding
Bottle Design
Reheat stretch blow machinery
Single stage machinery
One stage vs. two stage machinery
PET bottles must be designed with the blow molding process and the final application in mind. Once the structural functions of the bottle have been satisfied, many options for aesthetic appeal are available. Here are a few examples of issues which may need to be considered when developing a new PET bottle design.
A carbonated soft drink (CSD) is typically pressurized with 4 volumes or atmospheres of carbon dioxide pressure, so a CSD bottle must be designed not only to withstand the filler pressure but also to hold its shape during long-term storage under internal pressure. Proper base design and enough weight or wall thickness are important.
The weight of a stack of filled bottle cases applies quite a bit of downwards force on the bottles in the bottom row unless the cases have load-bearing dividers, so the bottles’ top load strength is important.
Bottles which have been light-weighted to minimize cost may need ribs added to provide enough rigidity to pick up the bottle without collapsing.
Juice and other perishable products are often hot-filled under conditions which would cause standard PET bottles to shrink and deform. Hot-Fill bottles are designed with neck finishes which will not deform when heated, bases which resist deformation, and vacuum panels to control the bottle collapse which occurs when the hot contents cool and shrink. Hot-Fill bottles are also blow molded under special conditions in heated blow molds.
Very flat panels are often chosen for aesthetic reasons. Because of the stresses involved in stretch-blow molding PET, flat panels often warp in uncontrollable ways. A certain amount of curvature in at least one plane is required for good bottle quality.
For these and a host of other reasons, it is important to work with experienced PET bottle designers when developing a new bottle.